JP3740825B2 - Fuel injection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection device for fuel injection.
[0002]
[Prior art]
2. Description of the Related Art As a fuel injection device applied to a diesel engine, a hydraulically operated electronically controlled fuel injection device as shown in Japanese Patent Publication No. 6-511524 is known.
[0003]
This hydraulically operated electronically controlled fuel injection system pressurizes oil to a high pressure with a high-pressure oil pump, temporarily stores the high-pressure oil in an oil rail, then supplies it to the injector, and this pressure actuates the booster piston inside the injector. At the same time, the fuel inside the injector is pressurized to the injection pressure by the pressure-increasing piston, and the needle valve is lifted by the pressurized fuel to perform fuel injection. Oil is engine lubricant.
[0004]
In general, a hydraulically operated electronically controlled fuel injection device is often provided in a large diesel engine such as a civil engineering machine or a construction machine, and an oil manifold is also integrally cast in a cylinder head of the engine. The injector and the oil manifold are connected via an oil passage formed in the cylinder head.
[0005]
The oil manifold is located close to the injectors to supply high pressure oil equally and responsively to each injector, and because engine lubricating oil whose viscosity changes depending on various operating conditions may be used. (The closer the oil manifold is to the injector, the better).
[0006]
[Problems to be solved by the invention]
By the way, the injector used in the electronically controlled fuel injection device turns the high pressure oil up and down at high speed by turning on / off high pressure oil with an electromagnetically driven poppet valve and opening and closing at high speed according to the engine speed. Therefore, it is easy to generate vibration.
[0007]
When the oil manifold is cast into the cylinder head as described above, there is no other resonating member, which is not a big problem, but a hydraulically operated electronically controlled fuel injection device is provided in a relatively small diesel engine such as a passenger car. In this case, there is a problem that the oil manifold easily picks up the vibration of the injector and easily generates noise.
[0008]
In small engines, the oil manifold cannot be cast into the cylinder head, and the oil manifold cannot be separated from the injector, so the oil manifold is installed on the cylinder head and attached directly to the injector. This is because the injector vibrates the oil manifold and the oil manifold emits noise.
[0009]
Accordingly, an object of the present invention is to provide a fuel injection device that solves the above-described problems and can reduce noise from an oil manifold without causing pressure loss or deterioration of responsiveness.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a pressure accumulator that is directly attached to a fuel injection nozzle, and includes a pressure accumulating container body that is hollow and has an opening, and a cap that liquid-tightly closes the opening of the pressure accumulating container body. A concave portion is formed in the cap, and a dynamic damper for attenuating vibration transmitted from the fuel injection nozzle is accommodated and attached in the concave portion .
[0011]
According to this, the vibration transmitted from the fuel injection nozzle to the fuel injection accumulator is attenuated by the dynamic damper , and noise can be reduced.
[0014]
Also, it may assume the accumulator is an oil rail electronically controlled hydraulic actuation type fuel injection device.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[0016]
FIG. 3 shows a hydraulically operated electronically controlled fuel injection device for a diesel engine according to an embodiment of the present invention. As shown in the drawing, a hydraulically operated electronically controlled fuel injection device 1 includes a plurality of (here, four) injectors 2 as fuel injection nozzles equal to the number of cylinders of an engine, and these injectors 2 include a fuel filter 5 and a fuel pump. 4 is connected to the fuel passage 6 so that the fuel in the fuel tank 3 is supplied by the fuel pump 4.
[0017]
The injector 2 is supplied with fuel from a fuel port (not shown) formed in the cylinder head.
[0018]
Each injector 2 is connected to an oil rail (accumulator) 8 serving as a common oil manifold. The oil rail 8 forms a pressure accumulating chamber, stores high pressure (about 3 to 20 MPa) oil (working fluid), and distributes and supplies the oil to each injector 2. Here, the engine lubricating oil is shared, and rationalization and cost reduction are achieved. It is optional to use special oil.
[0019]
As shown in FIGS. 1 and 4, the oil rail 8 is fixed by screwing onto the cylinder head 60, and has a hollow cylindrical pressure accumulating vessel main body 61 and openings at both ends of the pressure accumulating vessel main body 61. The cap 62 is closed liquid-tightly.
[0020]
The pressure accumulating vessel main body 61 is formed of a casting, and has a plurality of attachment portions 63 for fixing the injector 2 to the side portion. The mounting portion 63 is formed with a through hole 64 for feeding oil into the injector 2 and two screw holes 65 so that the injector 2 is firmly fixed by a U-shaped mounting tool 90 in a plan view. It has become.
[0021]
Further, a joint 66 is provided at a side portion of the pressure accumulating vessel main body 61 so as to connect a high-pressure oil passage 10 for sending high-pressure oil discharged from the high-pressure oil pump 9 as shown in FIG. It has become.
[0022]
As shown in FIGS. 1 and 2, the cap 62 is formed in a bottomed cylindrical shape that is screwed into the pressure accumulating vessel main body 61, and is screwed into the pressure accumulating vessel main body 61 with the bottom 67 as a tip. It is like that. That is, the cap 62 is formed so as to exhibit a concave portion 74 in the center in a state where the cap 62 is screwed into the pressure accumulating vessel main body 61.
[0023]
More specifically, the cap 62 is formed of a metal that can sufficiently withstand high pressure, and is a cylindrical tube portion 68 that is inserted from the opening of the pressure accumulating vessel main body 61 and screwed into the inner surface of the pressure accumulating vessel main body 61. A bottom 67 that closes the distal end side in the insertion direction of the tubular portion 68, and an edge that is formed so as to expand in a ring shape radially outward from the rear end in the insertion direction of the tubular portion 68 and is in close contact with the end face of the pressure accumulating vessel body 61 Part 69.
[0024]
The cylinder portion 68 has a screw 91 that is screwed into the accumulator body 61 on the outer peripheral surface. The bottom portion 67 is formed with a projection 70 projecting toward the inside of the pressure accumulating vessel main body 61 at the center (center portion of the bottom surface), and a bolt 77 described later is screwed into the projection 70 from the outside of the pressure accumulating vessel main body 61. The screw hole 71 is formed. The screw hole 71 is formed up to the middle of the projecting portion 70 so that the liquid tightness of the bottom portion 67 is maintained.
[0025]
The edge portion 69 has a ring-shaped seal member 72 on the surface in contact with the end surface of the pressure accumulator body 61. The seal member 72 is formed of a material having elasticity and liquid tightness such as rubber and Teflon, and the internal oil does not leak through the cap 62. In addition, a notch 73 is formed on the inner peripheral edge of the edge 69 so as to widen a movable range of a weight 76 described later so that the weight 76 does not hit the cap 62.
[0026]
A dynamic damper 75 as vibration damping means is accommodated and attached in the recess 74 of the cap 62.
[0027]
The dynamic damper 75 includes a weight (mass) 76 formed in a mushroom shape, a bolt 77 inserted into the weight 76, and a rubber mount 78 interposed between the weight 76 and the bolt 77.
[0028]
The weight 76 is made of metal, and a through hole 79 for inserting the bolt 77 and a head receiving portion 81 for embedding the head 80 of the bolt 77 are formed on the mushroom-shaped shaft.
[0029]
The head receiving portion 81 has a hole formed in the same shape as the head 80 of the bolt 77 so that the head 80 of the bolt 77 can be embedded in the umbrella portion 82 of the weight 76 without any gap, and the weight 76 rotates on the shaft. As a result, the bolt 77 is also rotated together.
[0030]
In addition, the weight 76 is formed so that the umbrella portion 82 has a diameter substantially the same as the outer diameter of the pressure accumulating vessel body 61 and the root portion 83 has a diameter that can be appropriately separated and accommodated in the cylindrical portion 68 of the cap 62. It is formed compactly so as not to protrude from the pressure accumulating vessel main body 61.
[0031]
The rubber mount 78 is made of rubber formed in a cylindrical shape, and a first collar 84 for restricting the screwing depth of the bolt 77 is integrally joined to the inner peripheral side, and the through hole of the weight 76 is connected to the outer peripheral side. The second collar 85 in contact with 79 is joined together. Both ends of the first collar 84 protrude from the rubber mount 78, and the second collar 85 is formed to have the same length as the rubber mount 78.
[0032]
The oil rail 8 is supplied with high-pressure oil discharged from a high-pressure oil pump 9 (pump) through a high-pressure oil passage 10. The high-pressure oil pump 9 is driven by engine power.
[0033]
The oil rail pressure is controlled by a pressure control valve 11 provided on the discharge side of the high pressure oil pump 9. That is, the pressure control valve 11 controls the internal pressure of the oil rail 8 by discharging a part of the oil discharged from the high pressure oil pump 9 to the oil pan 13 through the oil return passage 12 as appropriate.
[0034]
The oil in the oil pan 13 is sent to the high pressure oil pump 9 through the low pressure oil passage 14. That is, the low pressure oil passage 14 is provided with an oil pump 15 driven by the engine, which pressurizes the oil in the oil pan 13 to an appropriate pressure and supplies it to the high pressure oil pump 9. This is because the high-pressure oil pump 9 cannot be sucked by itself. In the low pressure oil passage 14, an oil filter 16 is provided on the discharge side of the oil pump 15. As usual, another oil pump 54 for supplying oil to each lubricating part of the engine is also provided.
[0035]
Further, the controller 18 comprising a CPU, ECU, etc. reads the engine operating state such as the current engine speed and engine load based on electric signals sent from various sensors, and compares these values with map values. A target injection amount is determined, an ON / OFF signal corresponding to the target injection amount is sent to the injector 2, and fuel injection control is executed.
[0036]
As shown in FIG. 5 and FIG. 6, the injector 2 integrally has a solenoid 24 at the top, and the controller 18 controls ON / OFF to raise and lower the poppet valve 26, so that the oil at the oil inlet 29 Has been introduced and blocked. High pressure oil is constantly supplied from the oil rail 8 to the oil inlet 29.
[0037]
Next, the operation will be described.
[0038]
As shown in FIGS. 5 and 6, when the solenoid 24 of the injector 2 is turned on, the poppet valve 26 is raised to introduce high-pressure oil into the injector 2, and the high-pressure oil introduced into the injector 2 increases. The pressure piston 31 is lowered against the urging force of the piston return spring 33.
[0039]
When the pressure-increasing piston 31 descends, the fuel in the fuel chamber 32 is pressurized through the plunger 46 and becomes high pressure. The pressurized fuel acts on the needle valve 35 through the high-pressure fuel port 34 and lifts the needle valve 35 against the urging force of the nozzle return spring 37 by the fuel pressure. As a result, high-pressure fuel is injected from the injection hole 38.
[0040]
On the other hand, when the solenoid 24 is turned off, the poppet valve 26 is lowered to stop the introduction of oil. The internal high-pressure oil is discharged from an oil discharge port 53 shown in FIG. Since the injector 2 is completely accommodated in the head cover, the oil is discharged onto the cylinder head 60 and returned to the oil pan through the cylinder head and the cylinder body.
[0041]
In this way, the injector 2 turns on and off the solenoid 24 in accordance with the engine speed, and raises and lowers the poppet valve 26 and the pressure increasing piston 31 each time. As a result, the injector 2 vibrates, and the vibration is transmitted to the oil rail 8 fixed to the injector 2.
[0042]
The vibration transmitted to the oil rail 8 is also transmitted to the dynamic damper 75 and vibrates the weight 76 via the rubber mount 78. At this time, the weight 76 vibrates so as to cancel the vibration of the oil rail 8 and greatly attenuates particularly disturbing vibration of 3 to 4 KHz.
[0043]
Moreover, since the notch 73 is formed in the edge of the inner peripheral side of the edge part of the cap 62, when the weight 76 vibrates, the weight 76 does not hit the cap 62, and a new noise is not emitted. .
[0044]
Thus, since the dynamic damper 75 for attenuating the vibration transmitted from the injector 2 is provided on the oil rail 8 directly attached to the injector 2, the vibration transmitted to the oil rail 8 can be effectively damped. And noise from the oil rail 8 can be prevented.
[0045]
In addition, since the concave portion 74 is formed in the cap 62 that liquid-tightly closes the opening of the pressure accumulating vessel main body 61 and the dynamic damper 75 is accommodated in the concave portion 74, the dynamic damper 75 does not protrude from the accumulator main body 61. It can be made compact.
[0046]
Then, a through hole 79 is formed in the weight 76, a cylindrical rubber mount 78 is inserted into the through hole 79, a bolt 77 is inserted into the rubber mount 78, and screwed into the cap 62 to be fixed. Since the dynamic damper 75 is formed, the dynamic damper 75 can have a simple structure.
[0047]
Further, since the head 80 of the bolt 77 is embedded in the head receiving portion 81 of the weight 76 and rotates integrally, the head 80 of the bolt 77 can be made compact without protruding from the weight 76, and a wrench can be obtained. The cap 62 can be easily attached to and detached from the cap 62 without using a tool such as the above.
[0048]
Further, since the cylindrical rubber mount 78 is sandwiched between the first collar 84 and the second collar 85 from the inner peripheral side and the outer peripheral side, the assembling work can be facilitated, and the minute amount in the through hole 79 of the weight 76 can be facilitated. It is possible to prevent an extremely biased force from acting on a part of the rubber mount 78 due to unevenness and the like, and the vibration of the oil rail 8 can be attenuated stably.
[0049]
【The invention's effect】
The present invention exhibits the following excellent effects.
[0050]
(1) The vibration of the oil rail can be absorbed, and noise from the oil rail can be prevented.
[0051]
(2) The dynamic damper can be compactly attached to the oil rail.
[Brief description of the drawings]
FIG. 1 is a side view of an oil rail showing a preferred embodiment of the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is a schematic explanatory diagram of a hydraulically operated electronically controlled fuel injection device.
FIG. 4 is a bird's-eye view of an oil rail and an injector.
FIG. 5 is a schematic explanatory diagram of an injector.
FIG. 6 is a schematic explanatory diagram of an injector.
[Explanation of symbols]
1 Hydraulically operated electronically controlled fuel injection system (fuel injection system)
2 Injector (fuel injection nozzle)
8 Oil rail (accumulator)
61 Pressure Accumulation Container Body 62 Cap 74 Recess 75 Dynamic Damper (Vibration Damping Means)

Claims (2)

A pressure accumulator directly attached to the fuel injection nozzle includes a pressure accumulating container main body having a hollow and opening and a cap that liquid-tightly closes the opening of the pressure accumulating container main body. A fuel injection apparatus, wherein a dynamic damper for attenuating vibration transmitted from the fuel injection nozzle is housed and attached . The fuel injection device according to claim 1, wherein the pressure accumulator is an oil rail of a hydraulically operated electronically controlled fuel injection device.

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